1. Field of the Invention
This invention lies in the field of art relating to a lubricating oil composition adapted for use between a plurality of moving surfaces with which the fluid composition is in contact for the purpose of reducing the friction between these surfaces and to provide protection from wear and corrosion. These lubricant compositions tend to deteriorate under conditions of use with the attendant formation of sludge, lacquer and carbonaceous or resinous materials which adhere to the engine parts, particularly the piston rings, grooves and skirts, and cyclinder walls thus reducing the operating efficiency of the engine. To counteract the formation of these deposits, and/or to ameliorate the effects of such deposits, certain chemical additives have been found, which when added to a lubricating oil, have the ability to minimize the formation of the deposits or to maintain the deposits formed suspended in the oil so that the engine is kept clean and in efficient operating condition for extended periods of time. These agents are known in the art to which this invention pertains as detergents, dispersants or detergent-dispersants. Metal organic compounds are particularly useful in this respect and are exemplified by the oil-soluble zinc, calcium and barium salts of petroleum sulfonic acids, alkylated hydroxy benzoic acids, dialkyl dithiophosphoric acids and the like.
There are drawbacks associated with the use of organic metal salts in a lubricating oil composition for an internal combustion engine. A major drawback is that the metal salts formed by neutralization of the acids resulting from the combustion process are generally insoluble in the lubricating oil composition. More importantly, these insoluble metal salts occur as hard deposits on the piston rings, piston skirts or the cylinder liners and in the groove of the engine. These hard deposits are believed to be a major contributor to the wear that is experienced in an internal combustion engine. This problem is particularly acute with compression ignition engines, such as diesel engines, wherein the engine oil is subjected to extremely high temperature and compression stresses.
It is an object of the present invention to provide a new class of compounds which are useful as additives in lubricating oil compositions.
It is another object to provide an improved lubricating oil composition for an internal combustion engine.
It is a further object to provide a deposits-modifying additive for lubricants which is effective for reducing engine wear.
It is another object to provide a lubricating oil composition useful in diesel engines.
2. Description of the Prior Art
U.S. Pat. No. 3,796,663 discloses the preparation and use of an N-hydroxy hydrocarbyl-substituted succinimide in a lubricating oil composition.
U.S. Pat. No. 4,104,182 discloses N-alkoxy hydrocarbyl succinimides as deposit modifiers for lubricating oil compositions.
A copending application, Ser. No. 149,223 filed on May 12, 1980 discloses hydrocarbyl carbamidopropanamide and their preparation and use.
The disclosures of the above are incorporated herein by reference.